Magnetron vacuum tube



P. G. CHEVlGNY MAGNETRON VACUUM TUBE April 29, 1947.

Filed March 26, 1.945

3 Sheets-Sheet 1 IN VEN TOR PflUL e. CHEWGNY BY ATTOMWEZY April 29, 1947. P. G. CHEVIGNY MAGNETRON VACUUM TUBE Filed March 26, 1945 3 Sheets-Sheet 2 INVEN PHI/L a. cwEv/ y ATTORAGL'Y I April 29, 1947- P. G. CHEVIGNY 2,419,536

MAGNETRON VACUUM TUBE Filed March 26, 1943 s Sheets-Sheet s I N VEN TOR. RqUL Ci. CHE V/GN Y AITOMY Patented Apr. 29, 1947 MAGNETRON VACUUM TUBE Paul Georges Chevigny, New York, N. Y., assignor to Federal Telephone and Radio Corporation, Newark, N. J-., a corporation of Delaware Application March 26, 1943, Serial No. 481,314

17 Claims.

This invention relates to improvements in vacuum tubes, and more particularly to magnetron oscillators adapted to provide high power at ultra-high frequencies.

An object of this invention is to provide a novel vacuum tube structure suitable for operation at extremely high frequencies, which at the same time is capable of handling large amounts of power.

Another object of this invention is directed to an improved magnetron oscillator having a high anode heat dissipation and being capable of handling large amounts of power.

A further object of this invention is directed to an improved magnetron oscillator in which theanode is readily capable of being cooled.

An additional object of this invention is to provide a magnetron oscillator in which a sealed hollow pipe serving both as an anode and as a tank circuit, projects from a sealed cathode support.

Other objects will become apparent from the following description taken in connection with the attached drawings showing several illustrative improvements of the invention, and wherein:

Fig. 1' is a longitudinal cross-sectional view of a preferred form of magnetron oscillator according to the present invention;

Fig. 2 is a transverse cross-sectional view taken along the line lIII of Fig. 1;

Fig. 3 is an enlarged cross-sectional view taken along the line III-III of Fig. 1;

Fig. 4 is an enlarged cross-sectional view of the coupling end of the magnetron illustrated in Fig. 1; p

Fig. 5 is an enlarged cross-sectional view of a modified form of coupling end;

Fig. 6 is an end view of the coupling device illustrated in Fig. 5;

Fig. 7 is an enlarged cross-sectional view of a further modified form of coupling end for the magnetron;

Fig. 8 is an enlarged cross-sectional view of still another form of coupling end which may be used with the magnetron of Fig, 1; v

Fig. 9 is a transverse cross-sectional view taken along the line 1K of Fig. 8; and

Fig. 10 is a partial enlarged cross-sectional view of a modified form of cathode structure which may be used in the magnetron illustrated in Fig. 1.

1 The vacuum tube according to the present invention is, as illustrated in Figs. 1 to 4 inclusive, of the magnetron type utilizing a hollow pipe I0, LIV-both as an anode for the tube and. as a hollow resonant chamber.

2 The two outwardly extending portions Ill, III of the pipe are connected by'a square portion II of reduced size, and in accordance with the preferred form of the present invention, the center bore of the pipe may be'formed, for example, square, as is clearly shown in Figs. 2 and 3, but other shapes may be used, as desired. A cathode I2 which may be in the form of a hollow nickel cylinder coated with a suitable electron emissive material, such as a barium carbonate mixture, or a strontium carbonate mixture, is positioned within a transverse opening I3 extending through the reduced portion II of the pipe. About the ends of the opening I3 are attached, on opposite sides, a pair of copper cup-shaped members I4, I4 having a central opening disposed about and'of the same size as the transverse opening I3. A second pair of smaller copper cup-shaped members I6, I6 are respectively positioned within the cup-shaped members I4, I4 and the peripheries of the two nestled cup-shaped members are interconnected by means such as the annular glass seals I8 and I8 respectively.

One end of the cylindrical cathode I2 is at tached to the bottom of one of the smaller cupshaped members I6 as through the end shield 20. Cathode leads 22, 22' extend outwardly through a center bore in the opposite magnets 24, 24. The lead 22 is attached to the top side of the bottom of the cup-shaped member I6, while the, lead 22' is attached to one end of a spiral heating element 26, the other end of which may be attached to theend shield 20 of the cathode cylinder I2. The lead 22' projects through a suitable opening in the opposite end shield 28 of the cylindrical cathode I2 and passes through and is supported by the bottom of the cup-shaped member I6. It will thus be seen that the oathode supporting structure is formed of two individual units sealed to the narrowed portion II of the hollow pipe and so shaped as to receive the magnets 24, 24'. The opening I3 in the narrow portion II of the hollow pipe permits an advantageous concentration of the magnetic field in the space between the cathode I2 and the surrounding portion of the hollow pipe forming the anode. The bottoms of the cup-shaped members I6, I6 provide a screen which prevents radiation from passing between the surface of the cathode and the outer cup-shaped members I4, I4. I

The outward extension of the pipe as in portions I!) I0 projecting from the electrode section of ,the, magnetron, permits a. ready cooling of such pipe as by the formation of cooling fins 30 on the surface of these ends, or by the use of any other cooling means, as will be apparent to those skilled in this art. One end IQ of the hollow pipe is covered with a cap 32 which may be brazed to the pipe itself to form an air-tight joint and serve as a reflector. The other end Iii may be formed with a coupling loop as is more clearly illustrated in Fig. 4. This end is covered by a cap 32' having an opening therethrough to which is connected a hollow sleeve 3d projecting outwardly of the cap. The outer end of the sleeve 34 is sealed with a glass bead 36 which, at the same time, serves to support a loop 38 projecting inwardly through the sleeve 34 to within the hollow pipe end Ill. The loop 33 serves to conple the magnetron oscillator with another device, as exemplified, by way of example, by the surrounding pipe 40.

Another arrangement to provide coupling from the magnetron is illustrated in Figs. and 6. In this case the hollow end 2H) of the magnetron oscillator is provided with the cap 232. Between the cap 232 and the pipe end 2 if! is positioned a copper or other metal disk 210 having a narrow slot 212 therethrough. The outside of the pipe is sealed by means of a mica disk 214 placed over the outer side of the copper disk 2'10 and sealed beneath the cap 232. For sealing purposes, a suitable fusing enamel may be placed about the edge of the mica disk.

A slightly difierent form of coupling is illustrated in Fig. 7. In this case the hollow pipe end am is covered by an end cap 332', and between the cap and pipe end is positioned a copper disk 31!] having a narrow slot 3'12. A mica disk 3'14 is placed over the opposite side of the copper disk 316 while a second copper disk 380 having a narrow slot 382, aligned with the slot 312, is positioned about the outside of the mica disk and pressed against the same through the action of the cap 3-32: By this arrangement the mica disk is protected, as compared with the structure illustrated in Figs. 5 and 6.

A still further coupling arrangement is illustrated in Figs. 8 and 9. In this case the hollow pipe end 4H) is formed with a reduced section 492 about which is connected an end cap 494 provided with a narrow slot 59%. The cap 594 may be attached to the reduced section 492 by any suit-able means such as screws 568. A. copper sleeve 5B?) is sealed at one end about the larger portion of the pipe end did, the other end of this copper sleeve spreads outwardly for sealing connection with the periphery of a, glass cup 562 which surrounds and encloses the reduced portion 492 of the hollow pipe and its attached slotted cap 695. The larger portion of the hollow pipe 4H! may also be provided with a radial flange 498 to which may be threaded a hollow pipe Mil of the device to which coupling is desired. H

The specific type of cathode illustrated in Fig. 1 may be replaced by other types of known cathodes. For example, in Fig. 1G, I have illustrated an adaptation of a cathode structure such as illustrated in my copending application, S. N. 474,968, filed, February 6, 1943, in which the electron emitting surface is formed by a helical coil IIZ wound on spaced supports I56 and heated by bombardment from a spiral filament I26. In this case the supporting rods B are mounted from the underside of the bottom of the cupshaped member I6 through an inverted cup I52,

while the filament I26 is mounted on a central supporting rod I54 which serves as an' inner filament structure. The other end of the filament I26 is connected to a hollow tubular conductor I56 which projects outwardly through the bottom of the cup-shaped member I6 and through a suitable bore in the magnet 24'. The outer end of the tubular conductor I56 is sealed as by a glass bead I5! which also serves as an outer support for the rod I 54. The rod I54 may be held within the tubular conductor I56 as by spaced insulators I58 and I60.

While I have described above the principles of my invention in connection with certain specific structure and particular modification thereof, it is to be clearly understood that this description is made only by way of example and not as a limitation on the scope of my invention as set forth in the objects and the accompanying claims.

I claim:

1. An electron discharge device including, an anode comprising a hollow metal pipe having a transverse opening therethrough intermediate its ends, means sealing one end of said pipe, a cathode extending through the transverse opening in said pipe and positioned substantially centrally within the hollow pipe, means attached to the opposite sides of said pipe about said transverse opening sealing said opening and supportin said cathode, magnets positioned on opposite sides of said hollow pipe and extending outwardly from said transverse opening, and sealing means attached to the other end of said hollow pipe.

2. The combination according to claim 1, in which said last sealing means includes a cap on the other end of said hollow pipe, a hollow sleeve extending through and projecting outwardly from said cap, a COIJlpliHg'IOOD extending through said sleeve, having one end positioned within the hollow pipe and the other end projecting beyond the outer end of said sleeve, and a seal in the outer end of said sleeve through which said loop passes.

3. The combination according to claim 1, in which said last sealing means includes a cap having a central opening on the other end of said hollow pipe, a metal disk provided with a narrow coupling slot intermediate said cap and the said other end of said pipe, and a mica disk sealed to said cap, covering said slot and the outside of said metal disk.

4. The combination according to claim-1, in which said'last sealing means includes a cap having a central opening on the other end of said hollow pipe, a metal disk provided witha narrow coupling slot intermediate said cap and the said other end of said pipe, a mica disk sealed to said cap, covering said slot-and the outside of said metal disk, and a second metal disk covering said mica disk, and provided with a narrow slot aligned with the slot in the firstvmetal disk.

5. The combination according to claim 1, in combination with a metal cap having a narrow slot attached on the other end of said hollow pipe, and in which said last sealing means comprises insulating means sealed to the said other end of the pipe and surrounding said slotted metal cap. V

6. The combination according to claim 1, in

combination with a metal cap having a narrow slot attached on the other end of said hollow pipe, and in which said last sealing means'comprises a glass cup surrounding said other pipe end and said slotted cap, and a'metal sleevesecured at one end about the said other end of the hollow pipe, and at its other end sealed to the periphery of said glass cup.

7. An electron discharge device including, a hollow metal pipe having a transverse opening therethrough, a pair of metallic cup-shaped members each having a hole in its bottom, respectively positioned on opposite sides of said pipe about the opening therethrough, the holes in the bottoms of the cup-shaped members being aligned with the opening through said pipe, a pair of second smaller metal cup-shaped members respectively nestled within the first cup-shaped members with the bottoms of the first cup-shaped members spaced from the bottoms of the second cup-shaped members, sealing means interconnecting the peripheries of each pair of nestled cup-shaped members, a cathode supported between the opposed bottoms of the smaller cupshaped members and positioned within the hollow metal pipe, a magnet positioned within each smaller cup-shaped member, means sealing one end of said hollow pipe and coupling means con nected to the other end of said hollow pipe.

8. The combination according to claim 7, in which the inside of said hollow pipe is formed as a substantially square bore and the outer surface of said pipe is formed substantially square adjacent the said openings, in combination with radially extending fins on both ends of said pipe.

9. The combination according to claim 7, in which said coupling means includes a cap on the other end of said hollow pipe, a hollow sleeve extending through and projecting outwardly from said cap, a loop extending through said sleeve, having one end positioned within the hollow pipe and the other end projecting beyond the outer end of said sleeve, and sealing means in the outer end of said sleeve through which said loop passes.

10. The combination according to claim '7, in which said coupling means includes a cap having a central opening on the other end of said hollow pipe, a metal disk provided with a narrow slot intermediate said cap and the said other end of said pipe, and a mica disk sealed to said cap, covering said slot and the outside of said metal disk.

11. The combination according to claim 7, in which said coupling means includes a cap having a central opening on the other end of said hollow pipe, a metal disk provided with a narrow slot intermediate said cap and the said other end of said pipe, 2. mica disk sealed to said cap, covering said slot and the outside of said metal disk, and a second metal disk covering said mica disk, and provided with a narrow slot aligned with the slot in the first metal disk,

12, The combination according to claim 7, in which said coupling means includes a metal cap having a narrow slot attached on the other end of said hollow pipe and insulating means sealed to the said other end of the pipe and surrounding said slotted metal cap.

13. The combination according to claim 7, in which said coupling means includes a metal cap having a narrow slot attached on the other end of said hollow pipe, a glass cup surrounding said other pipe end and said slotted cap, and a metal sleeve secured at one end about the said other end of the hollow pipe, and at its other end sealed to the periphery of said glass cup.

which said cathode comprises means forming a hollow cylindrical electron-emitting surface and a heating coil within said cylindrical surface, in combination with means attaching said surfaceforming means to the underside ofthe bottom of one of said smaller cup-shaped members, and means connected to said heating coil attached to the bottom of the other of said smaller cupshaped members.

15. The combination according to claim 7, in which said cathode comprises means forming a hollow cylindrical electron-emitting surface and a heating coil within said cylindrical surface, in combination with means attaching said surfaceforming means to the underside of the bottom of one of said smaller cup-shaped members, means attaching one end of said heating coil to said last means, and means connected to the other end of said heating coil and attached to the bottom of the other of said smaller cup-shaped members.

16. The combination according to claim 7, in which said cathode comprises means forming a hollow cylindrical electron-emitting surface and a heating coil within said cylindrical surface, in combination with means attaching said surfaceforming means to the underside of the bottom of one of said smaller cup-shaped members, means attaching one end of said heating coil to said last means, one outwardly projecting cathode lead attached to the upper side of the bottom of the one of said smaller cup-shaped members, and a second outwardly projecting cathode lead connected to the other end of said heating coil and extending through the bottom of the other of the smaller cup-shaped members, said magnets each being provided with a substantially central bore for permitting outward passage of said cathode leads.

17. An electron discharge device including, an anode comprising a hollow metal pipe having a transverse opening therethrough intermediate its ends, said hollow pipe having a substantially square bore and the outer surface of said pipe being substantially square adjacent said transverse opening, means sealing one end of said pipe, a cathode extending through the transverse opening in said pipe and positioned substantially centrally within the hollow pipe, means attached to the opposite sides of said pipe about said transverse opening sealing said opening and supporting said cathode, magnets positioned on opposite sides of said hollow pipe and extending outwardly from said transverse opening, and sealing means attached to the other end of said hollow pipe.

PAUL GEORGES CHEVIGNY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,282,856 Engbert May 12, 1942 2,108,640 Bieling Feb. 15, 1938 2,163,156 Samuel June 20, 1939 FOREIGN PATENTS Number Country Date 509,102 British July 11, 1939 

